1. Field of the Invention
The present inveniton relates to a charge completion detector. More specifically, the present invention relates to a charge completion detector which detects the time of completion of charging of a secondary cell such as a Ni-Cd battery, lead-acid battery and the like, in which the change in temperature at the completion of charging of the secondary cell is detected utilizing Seebeck effect.
2. Description of the Prior Art
Detectors detecting changes of temperature during charging of secondary cells, detectors detecting the rise of temperature of the battery itself by attaching a thermistor and the like on the battery, and detectors detecting the pressure of gas generated at the final stage of charging in the battery box have been known as detectors of charging secondary cells such as Ni-Cd batteries.
However, these charge detectors cannot precisely detect the time of charge completion, because the rate of rise of temperature, the gas pressure and the voltage at charge completion of the battery are changed dependent on the temperature of the atmosphere surrounding the battery. If means for correcting fluctuation caused by the environmental temperature is provided, the time of charge completion can be precisely detected. However, it requires complicated processing circuits and portions for detecting the environmental temperature.
Detectors detecting the peak of changing voltage of the secondary cell in charging may possibly detect the completion of charging erroneously before the actual completion of charging, since the voltage of the secondary cell sometimes shows the peak immediately after the start of charging.